Radio central-station system



Feb. i4, 1928.

D. L. WOLF ET AL RADIO CENTRAL STATION SYSTEM Filed Jan. 20, 1.926

(Z (Kw-M7- Patented Feb. 14, 1928.

UNlTED STATES DDNALID L. WOLF AND ROY G. REEL, OF DENI$ON, IOWA.

RADIO CENTRAL-STATION SYSTEVI.

Application filed January 20, 1926. Serial No. 82,329.

This invention relates to a new and improved radio central station system and more particularly to a system whereby radio reproducers located at a distance from a plu- 5 rality of dilierently tuned receiving sets may be selectively connected to one of such sets. Radio sets capable of receiving distant stations consistently and etiiciently are expensive pieces oi apparatus with a considerable maintenance expense and requiring skilled tuning and operation in order to procure the best results. A further ditliculty with the use of a plurality of such sets in congested districts and in large apartment houses and hotels lies in the fact that improperly operated sets may reradiate and cause interference with the reception by neighboring sets, or sets having antenna located-within a considerable distance of the reradiating set.

It is an object of the present invention to provide a method and apparatus whereby subscribers to a radio distributing system, or tenants in a large building may be provided. with radio programs of their own selection without the necessity for the installation, maintenance and expert operation of individual receiving sets.

It is an additional object of this invention to provide apparatrs whereby the subscriber may quickly and easily select the desired station for reproduction through his local reproducer.

Other and further objects will appear as the description proceeds.

We have illustrated somewhat diagrammatically in the single figure which constitutes the accompanying drawing one form or construction which our invention may take. A plurality of radio receiving sets A-BCD and E are provided at some suitable central location, these sets being provided with a suitable antenna system which has not been shown. The sets are all capable of being independently tuned and may be handled by a single expert who can operate them for the highest etiiciency.

The battery sides 11, 12, 13, 14 and 15 of the output circuits of the receivers join in a common wire 16 from which the wire 17 leads to the jack 18 at one local station. The wire 19 leads from the wire 16 to the jack 20 at another local station and it is obvious that as many other local stations as desired may be similarly connected. -The opposite side of the jack 18 is connected to the variable resistance 21 which is controlled by the movable arm 22. The arm 22 is connected by wire 23 with the local battery 24. lhe solenoid 25 is connected across the wires 17 and 23, so as to include the battery 24 and resistance 21 in the circuit through the sclcnoid and reproducer 26.

The armature 27 of the solenoid is normally held at its limit of outward movement by the spring 28. in this position the. cross arm 29 is out of contact with any oi the switch points. llhe switch 30 is provided with a pluralityof points 31. all connected to the wire 23 and opposite these, points 31 it is provided with a plurality of points S3. 34, 35 and 36 connected to the plate side of the output circuits of the receiving A to E. respectirely.

'lhe reproducer 3? is provided with a solenoid 38 and switch 39 exactly similar to the arrangement just described in connection with the lines to the reproducer 26. Qbviously, any desired number of reproducer circuits be connected to the eceiving sets in the same manner and desired number of receiving sets may he incorpon ated in the central station.

it will he observed that with he glue of the jaclr 18 the circuit, which include battery 24; and solenoid 25, is broken a therefore, the spring 28 will carry the s noid switci to its outermost position, out contact with -11 to the receic' serted in y of the contacts connected rig sets. the plug a jaclr, the circuit is comp solenoid and with the resist? cft limit as shown in switch as rest-istancs cut in, the L throu c-i will he so limited into its outermost "meets the wire cot-ed recei 0 set A. With arin up the next contact sons of the resistanc out out, the current flow is greater an "W armature is drawn into the next cor'act position connecting the loud speaker to rereceiying set in this manner the reproducer may he selectively connected to any inc one of the receiving sets. Switching the r producer from one switch to another calls for no skill, but merely the moving of a switch from point to point.

If it is desired to always give the same station programs from the central station the switch points may be marked station letters, so the W moved to the station selected. If desired .certain of the units can regularly receive certain stations and others may be tuned at various times for stations giving particularly good programs at the moment, at the discretion of the central station operator, depending on receiving conditions. 'It will be understood that any suitable amplification may be provided in the receiving sets to take care of the large number 'of re reducers, which may be connected into t e output circuits. The individual reproducers may be provided with modulating or sound control devices, as is now customary with many reproducers onthe market, so that the volume of reproduction may be within the control of the user of the particular reproducer,

This control would afiect only his own reproducer. It will be noted that in order to cut off reproduction, it is-necessaryto withdraw the plug from the jack and this withdrawal serves to break the circuit of the local battery and this avoids drain on this aevaeaa .producers, a circuit for each reproducer, a

battery and solenoid switch local to each reproducer circuit and a variable resistance in each reproducer circuit whereby the operation of the solenoid may be controlled and the reproducer circuit selectively connected to one of the receiving set output circuits.

2. In combination with a plurality of radio receiving sets, an external output circuit for each set, a fplurality of radio reproducers, a circuit or each reproducer, a battery and solenoid local to each reproducer circuit, a multiple switch operated by said solenoid, said :switch having contacts connected to said reproducer circuit and other contacts connected to each of the receiver output circuits, and means adjacent said reproducer adapted to control the solenoid switch to selectively connect the reproducer to any one of the receiving sets.

3. In combination with a plurality of radio receiving sets, an external output circuit for each set, a plurality of radio reproducers, a circuit for each reproducer, a

battery and solenoid local to eachreproducer circuit, a multiple switch operated by said solenoid, said switch having contacts connected to said reproducer circuit and other contacts connected to each of the receiver output circuits, means to maintain the switch normally in the open position, and means adjacent the reproducer adapted to control the solenoid switch to selectively connect the reproducer to any one of the receiving sets. Signed at Denison, Crawford County, Iowa, this 12th day of January, 1926.

' DONALD L. WOLF. ROY G. KEHJ- 

